Datapoint2200

Datapoint 2200 Schematics and Documents

Schematics for the Datapoint 2200 processor (version 1, serial) transcribed from original documents. Also contains various original documents.

The schematics are in Kicad 5 format. To open them you will need to import the symbol library in Datapoint2200.lib.

NOTES:

• These documents are still a work in progress.
• Schematics have not been double checked or verified against original hardware.
• On the original schematics some of the connector pinouts are ambiguous. DO NOT rely on the data in this repository when working with original hardware.

Files

• 2200_Drawing_package.pdf - Original schematics and engineering drawings.
• 2200_Reference_Manual.pdf - The original instruction manual including the assembly instruction set.
• Datapoint2200.lib and .dcm - Kicab custom symbols (for Kicad 5).
• InstructionSet.txt - The instruction sets for both versions of the 2200 and the (very similar) Intel 8008.
• InstructionSet.xlsx - Spreadsheet version of the instruction sets (2200 and 8008) including comparisons against the Z80/8080.

Folders

Schematics for each board are in a separate folder.

The following lists the key boards of the Datapoint 2200 and the files making up each board.

Decoder

Board A4: This board generates the system clock, T-states and various processor/system timing signals, does I/O decoding and generates the sound signals to be sent to the speaker.

• Decoder: The main overview.
• IODecorder: Output signal decoding.
• Scheduler: System clock and timing signals generation.
• Speaker_Tape: Sound generation and misc tape signal logic.

Deflection Amplifier

Board A7: Driver for the CRT gun and it's X/Y co-ordinates. Not transcribed.

Demodulator

Board A3: Demodulator for the tape drives Not transcribed yet.

Display Control

Board A8: Video memory, character generator and display driver. Not transcribed yet.

Keyboard

Board A5: The keyboard Not transcribed yet.

Keyboard Logic

Board A9: Logic for the keyboard (i.e. the I/O handler). Not transcribed yet.

Memory

Boards A11-A14: The shift memory cards Not transcribed yet.

Modulator

Board A2: Modulator for the tape drives Not transcribed yet.

Motherboard

Not transcribed yet

Power Supply, Regulator

Board A1. Not transcribed.

Processor

Board A5: The processor itself.

• AddressRegister: The address register (counter).
• AddrRegAndStackControl: Controls reading data into the address register and program counter, incrementing the program counter, and the stack.
• ALU: The ALU and carry flag.
• ARegister: The A register and I/O bus.
• Flags: The flags (other than carry) and conditional jump/call/return handling.
• InstrDecdoing: Instruction decoding.
• IRegister: The instruction register and register decoding.
• Processor: The main overview.
• Registers1: The H and L registers and data bus logic.
• Registers2: The B, C, D and E registers.
• Stack: The stack and stack pointer, and memory card selection.
• Timing: Fetch-execute cycle, memory word sync, HALTing and running, clocking and miscellaneous.